export interface Defer<A, E> {
    promise: Promise<A>;
    resolve: (a: A) => Promise<A>;
    reject: (e: E) => Promise<A>;
}
export declare function createDefer<A, E>(): Defer<A, E>;
export declare function resolveDefer<A, E>(defer: Defer<A, E>, a: A, f: () => E | Promise<E>): Promise<A>;